It is recommended that blood be collected in a sterile fashion and have an anticoagulant and/or preservation solution added during collection so as to allow its subsequent use under the best sanitary safety conditions.
A bag system for collecting blood is already known, in particular from the document FR-2 808 693. This system includes means of collecting the fluid, a bag containing an anticoagulant and/or preservation solution for the fluid collected, and a collection bag intended to receive the fluid collected with the anticoagulant and/or preservation solution added.
To allow sterile collection of blood, the collection bag is in fluid communication with the collection means by means of a first flexible tube and with the bag containing the anticoagulant and/or preservation solution by means of a second flexible tube, so as to form a closed-circuit system.
This type of system is intended to be used in a collection machine including a peristaltic pump able to partially compress respectively the first and second tubes so as to allow the simultaneous supply to the collection bag of a controlled proportion blood and anticoagulant and/or preservation solution.
To this end, the operation must in particular dispose part of the second tube around a head of the pump so as to allow the supply of the collection bag with anticoagulant and/or preservation solution by partial compression of an area of the second tube.
In practice, this arrangement proves to be difficult and, in cases where it is not properly carried out, the flow of solution pumped does not correspond to that required. The result is therefore a possible deficit or excess of anticoagulant and/or preservation solution in the collection bag, which is detrimental because this solution must be present in a fixed quantity for the blood collected to be usable in the medical field.